How to view the query of another session in pg_stat_activity without being super user?

I have a Postgresql 9.2 database. Two users are created on this database. When I perform the following query as superuser, I can see everything. select * from pg_stat_activity However, is it possible to acheive the same result without being connected as superuser ? Which privilege/role should I grant/create to have the results that a superuser can see ?